[Scott Kozutsky]

As I recall, if your pneumatic systems remain under a certain pressure you don't need any lisence or regulation for safety (for things like baloons or other similar low pressure things, I forget the specific threshold and may be wrong). These baloons are therefore legal as they meet all relevant safety standards. Using fans might not be so legal because it can surely pump more than 1.10CFM and would therefore be an illegal compressor.

This is also the first year pneumatic tires have been "legal" without the rest of the pneumatic control system, as there is now a specific exemption. No one cared in previous years despite being illegal by the rigid, literal interpretation of the rules. W tread Versawheels are illegal per R6 but noone will call that either.

There are likely other ways to interpret the rules that will shift "legality" one way or the other. Regardless, I can't imagine an inspector calling any team out on this particular system.